In camera systems, miniaturization of lens barrels is highly demanded and heightening of an autofocus speed is required. With a focusing system composed of a plurality of focus lens groups, a stroke length is made shorter than that with the focusing system composed of a single focus lens group. Thus, an entire length of a lens barrel can be shortened and an autofocus speed is heightened. Particularly in macro lenses, a deterioration in a performance of macro regions can be improved.
For example, a lens barrel described in Patent Document 1 has a plurality of focus lens groups, and one motor drives the plurality of focus lens groups using a cam mechanism.